The purpose of this project is to investigate the mechanisms by which injured neurons regenerate their nerve fibers and to evaluate neuronal and extra-neuronal factors that may influence the establishment of functional connections. To this end, regeneration studies are being performed in order to investigate nerve fiber growth, trophic nerve function, and any selectivity or plasticity that may exist between the neuron and its appropriate end-organ. The interaction occurring between neurons and taste buds is being used as a model for the project since taste buds develop under the influence of the nerve, the nerve is required for the maintenance of the buds, and because the buds disappear after denervation and reappear after nerve fiber regeneration.